Unlike the image produced by conventional printing, an ink jet image is transferred to the image receptor without a great deal of force. Ink droplets are emitted from a nozzle and deposited on a receptor to form an image. Ink jet imaging is discussed by W. E. Hass, in Imaging Processes and Materials--Neblette's Eight Edition, J. Sturge, V. Walworth, and A. Shepp, Ed., van Nostrand Reinhold, New York, 1989, pp 379-384.
To obtain high quality images, the ink must be rapidly absorbed into the receptor so that little or no spreading of the droplet, with concurrent loss of resolution, occurs. Consequently, materials that are not absorptive, such as polymer films, are typically coated with an absorptive receptor layer to form ink jet receptor elements.
To avoid the problems associated with the use of organic solvents, ink jet receptor layers that can be coated from water or from mixtures of water and lower alcohols have been developed. Coating from organic solvents, especially chlorinated hydrocarbons, is frequently undesirable because of air pollution, solvent recovery, toxicity, and waste disposal considerations. Residual solvent also may remain in the coating and produce odor problems during use of the element.
Coating of the receptor layer onto certain types of substrates, especially deformable substrates and porous substrates, is difficult. Coating onto deformable substrates, such as static cling vinyl, i.e., untreated poly(vinyl chloride) about 50-150 micron thick, or onto adhesion backed vinyl, is difficult because the high temperature (about 120-125.degree. C.) used for drying the coating can lead to distortion of the substrate and/or delamination of the substrate either from the coating or from associated layers. Use of lower drying temperatures produces to unacceptably low throughput for the coating equipment and/or unacceptable solvent residue in the receptor layer. Coating onto porous substrates, such as acrylic primed spunbonded polypropylene, is difficult because the material absorbs the coating solution. A need exists for a method for preparing ink jet receptor elements that comprise receptor layers on difficult to coat substrates, especially deformable substrates and porous substrates.